Minimally invasive surgical techniques have become the method of choice for the treatment of certain cardiovascular diseases. During interventional cardiology procedures, small plastic tubes called catheters are inserted into the vasculature through a leg or an arm. These catheters are threaded to the appropriate location for the diagnostic or therapeutic procedure. The access or opening in the artery or vein is created by using the so-called Seldinger technique. The Seldinger procedure begins with the insertion of a hollow needle through the skin to puncture the desired blood vessel. Next a guidewire is inserted through the needle into the blood vessel. At this point the needle is withdrawn and the guidewire remains in place. An introducer sheath or cannula is placed over the guidewire and inserted into the vessel to dilate or stretch the vessel to the required diameter for catheter insertion. The introducer also seals against blood pressure, thus preventing bleeding from the puncture site while allowing access to the cannulated vessel. The introducer remains in place until the procedure is completed. After the procedure, the introducer is removed leaving a wound in the skin and an opening in the blood vessel. This injury is subject to significant bleeding because the patient usually receives blood thinners or anticoagulants to minimize or prevent clot formation during the intervention. While these medications make the procedure safer, they also make sealing the puncture site upon removal of the introducer more difficult. The effect of blood thinners is to reduce the clotting capacity of the blood meaning that it will take longer for cuts and injuries to heal. Historically, after removal of the introducer, manual pressure has been applied for up to several hours to the puncture site and subsequently the canulated extremity is immobilized for up to a full day until sufficient healing has occurred.
Using manual pressure increases hospital staff time, increases health care costs, is uncomfortable for the patient, and increases the time to ambulation. Vascular sealing devices have been developed to address these issues. U.S. Pat. Nos. 4,744,364; 4,852,560, and 4,890,612 describe a mechanical umbrella which is inserted into the opening of the vessel and seals against blood flow from the inside of the vessel. U.S. Pat. Nos. 5,391,183 and 5,437,631 describe a plug which mechanically fills tie hole in the extremity with a material while allowing natural healing of the vessel to occur. U.S. Pat. No. 5,413,571 teaches a device which enters the vessel to be sealed. Both of these methods have the added risk of potentially injecting foreign materials into the blood vessel which may cause added complications. U.S. Pat. No. 5,613,974 describes a method to mechanically seal the puncture site in the artery or vein with sutures much like closing an incision in the skin. These methods typically require a skilled person, require significant time and are relatively expensive. U.S. Pat. Nos. 5,728,132 and 5,626,601 describe the use of hemostatic agents such as fibrin activated blood to provide a mechanical seal at the wound site. The patients' blood is typically drawn prior to the procedure and activated before injection into the puncture site. For various reasons each of the above described methods have not been fully accepted by the medical community. Consequently, there is a continuing need to develop devices which address wound closure to reduce times and health care costs.